From 9d7abe183c913e3a5c6b6194fcb4d01e996604c1 Mon Sep 17 00:00:00 2001
From: sapphi-red <green@sapphi.red>
Date: Wed, 6 Jul 2022 02:06:18 +0900
Subject: [PATCH 01/10] feat: warn if watcher is not working on WSL2

---
 docs/config/build-options.md           |  7 +++
 docs/config/server-options.md          | 15 ++++-
 packages/vite/src/node/build.ts        | 43 +++++++++----
 packages/vite/src/node/server/index.ts | 42 ++++++++++---
 packages/vite/src/node/watcher.ts      | 83 ++++++++++++++++++++++++++
 5 files changed, 170 insertions(+), 20 deletions(-)
 create mode 100644 packages/vite/src/node/watcher.ts

diff --git a/docs/config/build-options.md b/docs/config/build-options.md
index f2c9598f752ada..fb55bec3a73d78 100644
--- a/docs/config/build-options.md
+++ b/docs/config/build-options.md
@@ -193,3 +193,10 @@ Limit for chunk size warnings (in kbs).
 - **Default:** `null`
 
 Set to `{}` to enable rollup watcher. This is mostly used in cases that involve build-only plugins or integrations processes.
+
+::: warning Using Vite on Windows Subsystem for Linux (WSL) 2
+
+There are cases that file system watching does not work with WSL2.
+See [`server.watch`](./server-options.md#server-watch) for more details.
+
+:::
diff --git a/docs/config/server-options.md b/docs/config/server-options.md
index 6a43117f2ff164..e66337b9915073 100644
--- a/docs/config/server-options.md
+++ b/docs/config/server-options.md
@@ -167,8 +167,6 @@ The error that appears in the Browser when the fallback happens can be ignored.
 
 File system watcher options to pass on to [chokidar](https://github.com/paulmillr/chokidar#api).
 
-When running Vite on Windows Subsystem for Linux (WSL) 2, if the project folder resides in a Windows filesystem, you'll need to set this option to `{ usePolling: true }`. This is due to [a WSL2 limitation](https://github.com/microsoft/WSL/issues/4739) with the Windows filesystem.
-
 The Vite server watcher skips `.git/` and `node_modules/` directories by default. If you want to watch a package inside `node_modules/`, you can pass a negated glob pattern to `server.watch.ignored`. That is:
 
 ```js
@@ -186,6 +184,19 @@ export default defineConfig({
 })
 ```
 
+::: warning Using Vite on Windows Subsystem for Linux (WSL) 2
+
+When running Vite on WSL2, if the project folder resides in a Windows filesystem, file system watching does not work without `{ usePolling: true }`. This is due to [a WSL2 limitation](https://github.com/microsoft/WSL/issues/4739) with the Windows filesystem.
+
+To make file system watching work, you could either:
+
+- **Recommended**: Move the project folder outside of a Windows filesystem.
+  - Accessing Windows filesystem from WSL2 is slow. Removing that overhead will improve performance.
+- Set `{ usePolling: true }`
+  - Note that [`usePolling` leads to high CPU utilization](https://github.com/paulmillr/chokidar#performance).
+
+:::
+
 ## server.middlewareMode
 
 - **Type:** `boolean`
diff --git a/packages/vite/src/node/build.ts b/packages/vite/src/node/build.ts
index 973dcef199d8ee..181fcf7d199e1c 100644
--- a/packages/vite/src/node/build.ts
+++ b/packages/vite/src/node/build.ts
@@ -21,6 +21,7 @@ import commonjsPlugin from '@rollup/plugin-commonjs'
 import type { RollupCommonJSOptions } from 'types/commonjs'
 import type { RollupDynamicImportVarsOptions } from 'types/dynamicImportVars'
 import type { TransformOptions } from 'esbuild'
+import { detectWhetherChokidarWithDefaultOptionWorks, isWSL2 } from './watcher'
 import type { InlineConfig, ResolvedConfig } from './config'
 import { isDepsOptimizerEnabled, resolveConfig } from './config'
 import { buildReporterPlugin } from './plugins/reporter'
@@ -502,22 +503,44 @@ async function doBuild(
       }
 
       const watcherOptions = config.build.watch
+      const resolvedChokidarOptions = {
+        ignoreInitial: true,
+        ignorePermissionErrors: true,
+        ...watcherOptions.chokidar,
+        ignored: [
+          '**/node_modules/**',
+          '**/.git/**',
+          ...(watcherOptions?.chokidar?.ignored || [])
+        ]
+      }
+
+      if (isWSL2 && resolvedChokidarOptions.usePolling === undefined) {
+        detectWhetherChokidarWithDefaultOptionWorks(config.root).then(
+          ({ result, warning }) => {
+            if (result === false) {
+              config.logger.warn(
+                colors.yellow(
+                  colors.bold(`(!) `) +
+                    'Default file system watching is not working with your setup due to the limitation of WSL2. ' +
+                    'Rebuild will not happen.' +
+                    'More information: https://vitejs.dev/config/server-options.html#server-watch'
+                )
+              )
+            }
+            if (warning) {
+              config.logger.warn(colors.yellow(warning))
+            }
+          }
+        )
+      }
+
       const { watch } = await import('rollup')
       const watcher = watch({
         ...rollupOptions,
         output,
         watch: {
           ...watcherOptions,
-          chokidar: {
-            ignoreInitial: true,
-            ignorePermissionErrors: true,
-            ...watcherOptions.chokidar,
-            ignored: [
-              '**/node_modules/**',
-              '**/.git/**',
-              ...(watcherOptions?.chokidar?.ignored || [])
-            ]
-          }
+          chokidar: resolvedChokidarOptions
         }
       })
 
diff --git a/packages/vite/src/node/server/index.ts b/packages/vite/src/node/server/index.ts
index d270c92bfd0e74..5385c3643c48a1 100644
--- a/packages/vite/src/node/server/index.ts
+++ b/packages/vite/src/node/server/index.ts
@@ -37,6 +37,7 @@ import { CLIENT_DIR } from '../constants'
 import type { Logger } from '../logger'
 import { printCommonServerUrls } from '../logger'
 import { invalidatePackageData } from '../packages'
+import { detectWhetherChokidarWithDefaultOptionWorks, isWSL2 } from '../watcher'
 import type { PluginContainer } from './pluginContainer'
 import { createPluginContainer } from './pluginContainer'
 import type { WebSocketServer } from './ws'
@@ -282,14 +283,8 @@ export async function createServer(
   )
   const { middlewareMode } = serverConfig
 
-  const middlewares = connect() as Connect.Server
-  const httpServer = middlewareMode
-    ? null
-    : await resolveHttpServer(serverConfig, middlewares, httpsOptions)
-  const ws = createWebSocketServer(httpServer, config, httpsOptions)
-
   const { ignored = [], ...watchOptions } = serverConfig.watch || {}
-  const watcher = chokidar.watch(path.resolve(root), {
+  const resolvedWatchOptions: chokidar.WatchOptions = {
     ignored: [
       '**/.git/**',
       '**/node_modules/**',
@@ -300,7 +295,38 @@ export async function createServer(
     ignorePermissionErrors: true,
     disableGlobbing: true,
     ...watchOptions
-  }) as FSWatcher
+  }
+
+  if (isWSL2 && resolvedWatchOptions.usePolling === undefined) {
+    detectWhetherChokidarWithDefaultOptionWorks(root).then(
+      ({ result, warning }) => {
+        if (result === false) {
+          config.logger.warn(
+            colors.yellow(
+              colors.bold(`(!) `) +
+                'Default file system watching is not working with your setup due to the limitation of WSL2. ' +
+                'HMR and other features will not work. ' +
+                'More information: https://vitejs.dev/config/server-options.html#server-watch'
+            )
+          )
+        }
+        if (warning) {
+          config.logger.warn(colors.yellow(warning))
+        }
+      }
+    )
+  }
+
+  const middlewares = connect() as Connect.Server
+  const httpServer = middlewareMode
+    ? null
+    : await resolveHttpServer(serverConfig, middlewares, httpsOptions)
+  const ws = createWebSocketServer(httpServer, config, httpsOptions)
+
+  const watcher = chokidar.watch(
+    path.resolve(root),
+    resolvedWatchOptions
+  ) as FSWatcher
 
   const moduleGraph: ModuleGraph = new ModuleGraph((url, ssr) =>
     container.resolveId(url, undefined, { ssr })
diff --git a/packages/vite/src/node/watcher.ts b/packages/vite/src/node/watcher.ts
new file mode 100644
index 00000000000000..921760efea0e07
--- /dev/null
+++ b/packages/vite/src/node/watcher.ts
@@ -0,0 +1,83 @@
+import fs from 'node:fs'
+import os from 'node:os'
+import path from 'node:path'
+import chokidar from 'chokidar'
+
+/**
+ * returns `true` for WSL2 including docker running on WSL2
+ *
+ * https://github.com/microsoft/WSL/issues/423#issuecomment-844418910
+ */
+export const isWSL2 = (() => {
+  const release = os.release()
+  // Example: `5.10.102.1-microsoft-standard-WSL2`
+  if (release.includes('WSL2')) {
+    // "Docker Desktop for Windows with WSL2 backend" and "Docker installed in WSL" comes here too
+    return true
+  }
+
+  // Windows Example: `10.0.19044`
+  // WSL1 Example: `4.4.0-19041-Microsoft`
+  // Docker Desktop for Windows with WSL2 backend Example: `5.10.76-linuxkit`
+  return false
+})()
+
+/**
+ * returns `true` when it works, `false` when it doesn't, `undefined` when it failed to detect
+ */
+export const detectWhetherChokidarWithDefaultOptionWorks = (
+  root: string,
+  timeout = 100
+): Promise<{ result: boolean | undefined; warning: string | undefined }> =>
+  new Promise((resolve) => {
+    const id = ('' + performance.now()).replace(/\./g, '')
+    const tempFileShort = `.chokidardetector.${id}.txt`
+    const tempFile = path.resolve(root, tempFileShort)
+
+    let wroteFile = false
+
+    let timeoutId: NodeJS.Timeout
+    const w = chokidar.watch(root, {
+      depth: 1,
+      disableGlobbing: true,
+      ignoreInitial: true
+    })
+    w.on('add', () => {
+      resolveWithCleanup(true)
+    })
+    w.on('error', () => {
+      resolveWithCleanup(undefined)
+    })
+    w.on('ready', () => {
+      fs.promises.writeFile(tempFile, 'detector', 'utf-8').then(
+        () => {
+          wroteFile = true
+        },
+        () => {
+          resolveWithCleanup(undefined)
+        }
+      )
+      timeoutId = setTimeout(() => {
+        resolveWithCleanup(false)
+      }, timeout)
+    })
+
+    let resolved = false
+    const resolveWithCleanup = async (result: boolean | undefined) => {
+      if (resolved) return
+      resolved = true
+
+      clearTimeout(timeoutId)
+      await w.close()
+
+      let warning: string | undefined
+      if (wroteFile) {
+        try {
+          await fs.promises.unlink(tempFile)
+        } catch {
+          warning = `Failed to remove temp file (${tempFileShort}). This file can be removed.`
+        }
+      }
+      resolve({ result, warning })
+    }
+  })

From 84f71e3f40f084c4d774ffc98ef4777fe0086130 Mon Sep 17 00:00:00 2001
From: sapphi-red <green@sapphi.red>
Date: Sat, 9 Jul 2022 23:23:11 +0900
Subject: [PATCH 02/10] fix: use edit event

---
 packages/vite/src/node/watcher.ts | 25 ++++++++++++++++---------
 1 file changed, 16 insertions(+), 9 deletions(-)

diff --git a/packages/vite/src/node/watcher.ts b/packages/vite/src/node/watcher.ts
index 921760efea0e07..e111bb298697c8 100644
--- a/packages/vite/src/node/watcher.ts
+++ b/packages/vite/src/node/watcher.ts
@@ -26,10 +26,12 @@ export const isWSL2 = (() => {
  * returns `true` when it works, `false` when it doesn't, `undefined` when it failed to detect
  */
 export const detectWhetherChokidarWithDefaultOptionWorks = (
-  root: string,
-  timeout = 100
+  root: string
 ): Promise<{ result: boolean | undefined; warning: string | undefined }> =>
   new Promise((resolve) => {
+    const editWait = 100
+    const detectWaitTimeout = 500
+
     const id = ('' + performance.now()).replace(/\./g, '')
     const tempFileShort = `.chokidardetector.${id}.txt`
     const tempFile = path.resolve(root, tempFileShort)
@@ -42,24 +44,29 @@ export const detectWhetherChokidarWithDefaultOptionWorks = (
       disableGlobbing: true,
       ignoreInitial: true
     })
-    w.on('add', () => {
+    // add works with WSL2, but edit does not work
+    w.on('edit', () => {
       resolveWithCleanup(true)
     })
     w.on('error', () => {
       resolveWithCleanup(undefined)
     })
     w.on('ready', () => {
-      fs.promises.writeFile(tempFile, 'detector', 'utf-8').then(
-        () => {
+      ;(async () => {
+        try {
+          await fs.promises.writeFile(tempFile, 'detector', 'utf-8')
           wroteFile = true
-        },
-        () => {
+          await new Promise((resolve) => setTimeout(resolve, editWait))
+          // edit file
+          await fs.promises.writeFile(tempFile, 'detector2', 'utf-8')
+        } catch {
           resolveWithCleanup(undefined)
         }
-      )
+      })()
+
       timeoutId = setTimeout(() => {
         resolveWithCleanup(false)
-      }, timeout)
+      }, detectWaitTimeout)
     })
 
     let resolved = false

From 868808e22b8d48bdabfc38ebb38bcaeb719e9679 Mon Sep 17 00:00:00 2001
From: sapphi-red <green@sapphi.red>
Date: Sun, 10 Jul 2022 00:55:11 +0900
Subject: [PATCH 03/10] fix: use change

---
 packages/vite/src/node/watcher.ts | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/packages/vite/src/node/watcher.ts b/packages/vite/src/node/watcher.ts
index e111bb298697c8..0baecd9383bb0d 100644
--- a/packages/vite/src/node/watcher.ts
+++ b/packages/vite/src/node/watcher.ts
@@ -44,8 +44,8 @@ export const detectWhetherChokidarWithDefaultOptionWorks = (
       disableGlobbing: true,
       ignoreInitial: true
     })
-    // add works with WSL2, but edit does not work
-    w.on('edit', () => {
+    // add works with WSL2, but change does not work
+    w.on('change', () => {
       resolveWithCleanup(true)
     })
     w.on('error', () => {

From 7ff09162d105d2bb4e758158b1f8bf716dcba4ae Mon Sep 17 00:00:00 2001
From: sapphi-red <green@sapphi.red>
Date: Sun, 10 Jul 2022 01:43:43 +0900
Subject: [PATCH 04/10] fix: give up detection

The current detection somehow works with docker+wsl2, but it does not work with wsl2.
---
 packages/vite/src/node/build.ts        | 27 +++-----
 packages/vite/src/node/server/index.ts | 26 +++-----
 packages/vite/src/node/utils.ts        | 19 ++++++
 packages/vite/src/node/watcher.ts      | 90 --------------------------
 4 files changed, 37 insertions(+), 125 deletions(-)
 delete mode 100644 packages/vite/src/node/watcher.ts

diff --git a/packages/vite/src/node/build.ts b/packages/vite/src/node/build.ts
index 181fcf7d199e1c..2dd78e0741f348 100644
--- a/packages/vite/src/node/build.ts
+++ b/packages/vite/src/node/build.ts
@@ -21,13 +21,12 @@ import commonjsPlugin from '@rollup/plugin-commonjs'
 import type { RollupCommonJSOptions } from 'types/commonjs'
 import type { RollupDynamicImportVarsOptions } from 'types/dynamicImportVars'
 import type { TransformOptions } from 'esbuild'
-import { detectWhetherChokidarWithDefaultOptionWorks, isWSL2 } from './watcher'
 import type { InlineConfig, ResolvedConfig } from './config'
 import { isDepsOptimizerEnabled, resolveConfig } from './config'
 import { buildReporterPlugin } from './plugins/reporter'
 import { buildEsbuildPlugin } from './plugins/esbuild'
 import { terserPlugin } from './plugins/terser'
-import { copyDir, emptyDir, lookupFile, normalizePath } from './utils'
+import { copyDir, emptyDir, isWSL2, lookupFile, normalizePath } from './utils'
 import { manifestPlugin } from './plugins/manifest'
 import type { Logger } from './logger'
 import { dataURIPlugin } from './plugins/dataUri'
@@ -515,22 +514,14 @@ async function doBuild(
       }
 
       if (isWSL2 && resolvedChokidarOptions.usePolling === undefined) {
-        detectWhetherChokidarWithDefaultOptionWorks(config.root).then(
-          ({ result, warning }) => {
-            if (result === false) {
-              config.logger.warn(
-                colors.yellow(
-                  colors.bold(`(!) `) +
-                    'Default file system watching is not working with your setup due to the limitation of WSL2. ' +
-                    'Rebuild will not happen.' +
-                    'More information: https://vitejs.dev/config/server-options.html#server-watch'
-                )
-              )
-            }
-            if (warning) {
-              config.logger.warn(colors.yellow(warning))
-            }
-          }
+        config.logger.warn(
+          colors.yellow(
+            colors.bold(`(!) `) +
+              'Default file system watching might not work with your setup due to the limitation of WSL2. ' +
+              'Rebuild will not happen when file system watching is not working. ' +
+              'To suppress this warning, set true or false to "build.watch.usePolling". ' +
+              'More information: https://vitejs.dev/config/server-options.html#server-watch'
+          )
         )
       }
 
diff --git a/packages/vite/src/node/server/index.ts b/packages/vite/src/node/server/index.ts
index 5385c3643c48a1..4fae784f479c5a 100644
--- a/packages/vite/src/node/server/index.ts
+++ b/packages/vite/src/node/server/index.ts
@@ -17,6 +17,7 @@ import type { InlineConfig, ResolvedConfig } from '../config'
 import { isDepsOptimizerEnabled, resolveConfig } from '../config'
 import {
   isParentDirectory,
+  isWSL2,
   mergeConfig,
   normalizePath,
   resolveHostname
@@ -37,7 +38,6 @@ import { CLIENT_DIR } from '../constants'
 import type { Logger } from '../logger'
 import { printCommonServerUrls } from '../logger'
 import { invalidatePackageData } from '../packages'
-import { detectWhetherChokidarWithDefaultOptionWorks, isWSL2 } from '../watcher'
 import type { PluginContainer } from './pluginContainer'
 import { createPluginContainer } from './pluginContainer'
 import type { WebSocketServer } from './ws'
@@ -298,22 +298,14 @@ export async function createServer(
   }
 
   if (isWSL2 && resolvedWatchOptions.usePolling === undefined) {
-    detectWhetherChokidarWithDefaultOptionWorks(root).then(
-      ({ result, warning }) => {
-        if (result === false) {
-          config.logger.warn(
-            colors.yellow(
-              colors.bold(`(!) `) +
-                'Default file system watching is not working with your setup due to the limitation of WSL2. ' +
-                'HMR and other features will not work. ' +
-                'More information: https://vitejs.dev/config/server-options.html#server-watch'
-            )
-          )
-        }
-        if (warning) {
-          config.logger.warn(colors.yellow(warning))
-        }
-      }
+    config.logger.warn(
+      colors.yellow(
+        colors.bold(`(!) `) +
+          'Default file system watching might not work with your setup due to the limitation of WSL2. ' +
+          'HMR and other features will not work when file system watching is not working. ' +
+          'To suppress this warning, set true or false to "server.watch.usePolling". ' +
+          'More information: https://vitejs.dev/config/server-options.html#server-watch'
+      )
     )
   }
 
diff --git a/packages/vite/src/node/utils.ts b/packages/vite/src/node/utils.ts
index 0b0c205d80b9e4..fc9c1d59d1ab6e 100644
--- a/packages/vite/src/node/utils.ts
+++ b/packages/vite/src/node/utils.ts
@@ -1087,3 +1087,22 @@ export const isNonDriveRelativeAbsolutePath = (p: string): boolean => {
   if (!isWindows) return p.startsWith('/')
   return windowsDrivePathPrefixRE.test(p)
 }
+
+/**
+ * returns `true` for WSL2 including docker running on WSL2
+ *
+ * https://github.com/microsoft/WSL/issues/423#issuecomment-844418910
+ */
+export const isWSL2 = (() => {
+  const release = os.release()
+  // Example: `5.10.102.1-microsoft-standard-WSL2`
+  if (release.includes('WSL2')) {
+    // "Docker Desktop for Windows with WSL2 backend" and "Docker installed in WSL" comes here too
+    return true
+  }
+
+  // Windows Example: `10.0.19044`
+  // WSL1 Example: `4.4.0-19041-Microsoft`
+  // Docker Desktop for Windows with WSL2 backend Example: `5.10.76-linuxkit`
+  return false
+})()
diff --git a/packages/vite/src/node/watcher.ts b/packages/vite/src/node/watcher.ts
deleted file mode 100644
index 0baecd9383bb0d..00000000000000
--- a/packages/vite/src/node/watcher.ts
+++ /dev/null
@@ -1,90 +0,0 @@
-import fs from 'node:fs'
-import os from 'node:os'
-import path from 'node:path'
-import chokidar from 'chokidar'
-
-/**
- * returns `true` for WSL2 including docker running on WSL2
- *
- * https://github.com/microsoft/WSL/issues/423#issuecomment-844418910
- */
-export const isWSL2 = (() => {
-  const release = os.release()
-  // Example: `5.10.102.1-microsoft-standard-WSL2`
-  if (release.includes('WSL2')) {
-    // "Docker Desktop for Windows with WSL2 backend" and "Docker installed in WSL" comes here too
-    return true
-  }
-
-  // Windows Example: `10.0.19044`
-  // WSL1 Example: `4.4.0-19041-Microsoft`
-  // Docker Desktop for Windows with WSL2 backend Example: `5.10.76-linuxkit`
-  return false
-})()
-
-/**
- * returns `true` when it works, `false` when it doesn't, `undefined` when it failed to detect
- */
-export const detectWhetherChokidarWithDefaultOptionWorks = (
-  root: string
-): Promise<{ result: boolean | undefined; warning: string | undefined }> =>
-  new Promise((resolve) => {
-    const editWait = 100
-    const detectWaitTimeout = 500
-
-    const id = ('' + performance.now()).replace(/\./g, '')
-    const tempFileShort = `.chokidardetector.${id}.txt`
-    const tempFile = path.resolve(root, tempFileShort)
-
-    let wroteFile = false
-
-    let timeoutId: NodeJS.Timeout
-    const w = chokidar.watch(root, {
-      depth: 1,
-      disableGlobbing: true,
-      ignoreInitial: true
-    })
-    // add works with WSL2, but change does not work
-    w.on('change', () => {
-      resolveWithCleanup(true)
-    })
-    w.on('error', () => {
-      resolveWithCleanup(undefined)
-    })
-    w.on('ready', () => {
-      ;(async () => {
-        try {
-          await fs.promises.writeFile(tempFile, 'detector', 'utf-8')
-          wroteFile = true
-          await new Promise((resolve) => setTimeout(resolve, editWait))
-          // edit file
-          await fs.promises.writeFile(tempFile, 'detector2', 'utf-8')
-        } catch {
-          resolveWithCleanup(undefined)
-        }
-      })()
-
-      timeoutId = setTimeout(() => {
-        resolveWithCleanup(false)
-      }, detectWaitTimeout)
-    })
-
-    let resolved = false
-    const resolveWithCleanup = async (result: boolean | undefined) => {
-      if (resolved) return
-      resolved = true
-
-      clearTimeout(timeoutId)
-      await w.close()
-
-      let warning: string | undefined
-      if (wroteFile) {
-        try {
-          await fs.promises.unlink(tempFile)
-        } catch {
-          warning = `Failed to remove temp file (${tempFileShort}). This file can be removed.`
-        }
-      }
-      resolve({ result, warning })
-    }
-  })

From e8598bf9ad95dc99eefcf1b65c988b4093a937de Mon Sep 17 00:00:00 2001
From: sapphi-red <green@sapphi.red>
Date: Sun, 10 Jul 2022 02:06:51 +0900
Subject: [PATCH 05/10] docs: explain about wsl2 limitation more accurately

---
 docs/config/server-options.md | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/docs/config/server-options.md b/docs/config/server-options.md
index e66337b9915073..c83451db5a0e1e 100644
--- a/docs/config/server-options.md
+++ b/docs/config/server-options.md
@@ -186,12 +186,13 @@ export default defineConfig({
 
 ::: warning Using Vite on Windows Subsystem for Linux (WSL) 2
 
-When running Vite on WSL2, if the project folder resides in a Windows filesystem, file system watching does not work without `{ usePolling: true }`. This is due to [a WSL2 limitation](https://github.com/microsoft/WSL/issues/4739) with the Windows filesystem.
+When running Vite on WSL2 and a file is edited by Windows applications (non WSL2 process), file system watching does not work without `{ usePolling: true }`.
+This is due to [a WSL2 limitation](https://github.com/microsoft/WSL/issues/4739).
 
 To make file system watching work, you could either:
 
-- **Recommended**: Move the project folder outside of a Windows filesystem.
-  - Accessing Windows filesystem from WSL2 is slow. Removing that overhead will improve performance.
+- **Recommended**: Use WSL2 applications to edit your files.
+  - Also it is recommended to move the project folder outside of a Windows filesystem. Accessing Windows filesystem from WSL2 is slow. Removing that overhead will improve performance.
 - Set `{ usePolling: true }`
   - Note that [`usePolling` leads to high CPU utilization](https://github.com/paulmillr/chokidar#performance).
 

From fe4e7e68583e1798a6e1830b3d35ecaf8d6d6c40 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E7=BF=A0=20/=20green?= <green@sapphi.red>
Date: Mon, 11 Jul 2022 01:29:18 +0900
Subject: [PATCH 06/10] chore: update docs, thanks blu

Co-authored-by: Bjorn Lu <bjornlu.dev@gmail.com>
---
 docs/config/server-options.md | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/docs/config/server-options.md b/docs/config/server-options.md
index c83451db5a0e1e..f8629e9a33a35c 100644
--- a/docs/config/server-options.md
+++ b/docs/config/server-options.md
@@ -186,14 +186,13 @@ export default defineConfig({
 
 ::: warning Using Vite on Windows Subsystem for Linux (WSL) 2
 
-When running Vite on WSL2 and a file is edited by Windows applications (non WSL2 process), file system watching does not work without `{ usePolling: true }`.
-This is due to [a WSL2 limitation](https://github.com/microsoft/WSL/issues/4739).
+When running Vite on WSL2, file system watching does not work when a file is edited by Windows applications (non-WSL2 process). This is due to [a WSL2 limitation](https://github.com/microsoft/WSL/issues/4739).
 
-To make file system watching work, you could either:
+To fix it, you could either:
 
 - **Recommended**: Use WSL2 applications to edit your files.
-  - Also it is recommended to move the project folder outside of a Windows filesystem. Accessing Windows filesystem from WSL2 is slow. Removing that overhead will improve performance.
-- Set `{ usePolling: true }`
+  - It is also recommended to move the project folder outside of a Windows filesystem. Accessing Windows filesystem from WSL2 is slow. Removing that overhead will improve performance.
+- Set `{ usePolling: true }`.
   - Note that [`usePolling` leads to high CPU utilization](https://github.com/paulmillr/chokidar#performance).
 
 :::

From 0eda07177b87db379b1366c7f9a5273e927789b1 Mon Sep 17 00:00:00 2001
From: sapphi-red <green@sapphi.red>
Date: Mon, 11 Jul 2022 01:40:37 +0900
Subject: [PATCH 07/10] refactor: extract as resolveChokidarOptions

---
 packages/vite/src/node/build.ts        | 33 ++++++----------------
 packages/vite/src/node/server/index.ts | 32 ++++------------------
 packages/vite/src/node/watch.ts        | 38 ++++++++++++++++++++++++++
 3 files changed, 52 insertions(+), 51 deletions(-)
 create mode 100644 packages/vite/src/node/watch.ts

diff --git a/packages/vite/src/node/build.ts b/packages/vite/src/node/build.ts
index 2dd78e0741f348..4d23d572b10ac7 100644
--- a/packages/vite/src/node/build.ts
+++ b/packages/vite/src/node/build.ts
@@ -26,7 +26,7 @@ import { isDepsOptimizerEnabled, resolveConfig } from './config'
 import { buildReporterPlugin } from './plugins/reporter'
 import { buildEsbuildPlugin } from './plugins/esbuild'
 import { terserPlugin } from './plugins/terser'
-import { copyDir, emptyDir, isWSL2, lookupFile, normalizePath } from './utils'
+import { copyDir, emptyDir, lookupFile, normalizePath } from './utils'
 import { manifestPlugin } from './plugins/manifest'
 import type { Logger } from './logger'
 import { dataURIPlugin } from './plugins/dataUri'
@@ -48,6 +48,7 @@ import type { PackageData } from './packages'
 import { watchPackageDataPlugin } from './packages'
 import { ensureWatchPlugin } from './plugins/ensureWatch'
 import { ESBUILD_MODULES_TARGET, VERSION } from './constants'
+import { resolveChokidarOptions } from './watch'
 
 export interface BuildOptions {
   /**
@@ -501,36 +502,18 @@ async function doBuild(
         output.push(buildOutputOptions(outputs))
       }
 
-      const watcherOptions = config.build.watch
-      const resolvedChokidarOptions = {
-        ignoreInitial: true,
-        ignorePermissionErrors: true,
-        ...watcherOptions.chokidar,
-        ignored: [
-          '**/node_modules/**',
-          '**/.git/**',
-          ...(watcherOptions?.chokidar?.ignored || [])
-        ]
-      }
-
-      if (isWSL2 && resolvedChokidarOptions.usePolling === undefined) {
-        config.logger.warn(
-          colors.yellow(
-            colors.bold(`(!) `) +
-              'Default file system watching might not work with your setup due to the limitation of WSL2. ' +
-              'Rebuild will not happen when file system watching is not working. ' +
-              'To suppress this warning, set true or false to "build.watch.usePolling". ' +
-              'More information: https://vitejs.dev/config/server-options.html#server-watch'
-          )
-        )
-      }
+      const resolvedChokidarOptions = resolveChokidarOptions(
+        config.logger,
+        config.build.watch.chokidar,
+        'build.watch.chokidar'
+      )
 
       const { watch } = await import('rollup')
       const watcher = watch({
         ...rollupOptions,
         output,
         watch: {
-          ...watcherOptions,
+          ...config.build.watch,
           chokidar: resolvedChokidarOptions
         }
       })
diff --git a/packages/vite/src/node/server/index.ts b/packages/vite/src/node/server/index.ts
index 4fae784f479c5a..2e24a907f88836 100644
--- a/packages/vite/src/node/server/index.ts
+++ b/packages/vite/src/node/server/index.ts
@@ -17,7 +17,6 @@ import type { InlineConfig, ResolvedConfig } from '../config'
 import { isDepsOptimizerEnabled, resolveConfig } from '../config'
 import {
   isParentDirectory,
-  isWSL2,
   mergeConfig,
   normalizePath,
   resolveHostname
@@ -38,6 +37,7 @@ import { CLIENT_DIR } from '../constants'
 import type { Logger } from '../logger'
 import { printCommonServerUrls } from '../logger'
 import { invalidatePackageData } from '../packages'
+import { resolveChokidarOptions } from '../watch'
 import type { PluginContainer } from './pluginContainer'
 import { createPluginContainer } from './pluginContainer'
 import type { WebSocketServer } from './ws'
@@ -283,31 +283,11 @@ export async function createServer(
   )
   const { middlewareMode } = serverConfig
 
-  const { ignored = [], ...watchOptions } = serverConfig.watch || {}
-  const resolvedWatchOptions: chokidar.WatchOptions = {
-    ignored: [
-      '**/.git/**',
-      '**/node_modules/**',
-      '**/test-results/**', // Playwright
-      ...(Array.isArray(ignored) ? ignored : [ignored])
-    ],
-    ignoreInitial: true,
-    ignorePermissionErrors: true,
-    disableGlobbing: true,
-    ...watchOptions
-  }
-
-  if (isWSL2 && resolvedWatchOptions.usePolling === undefined) {
-    config.logger.warn(
-      colors.yellow(
-        colors.bold(`(!) `) +
-          'Default file system watching might not work with your setup due to the limitation of WSL2. ' +
-          'HMR and other features will not work when file system watching is not working. ' +
-          'To suppress this warning, set true or false to "server.watch.usePolling". ' +
-          'More information: https://vitejs.dev/config/server-options.html#server-watch'
-      )
-    )
-  }
+  const resolvedWatchOptions = resolveChokidarOptions(
+    config.logger,
+    { disableGlobbing: true, ...serverConfig.watch },
+    'server.watch'
+  )
 
   const middlewares = connect() as Connect.Server
   const httpServer = middlewareMode
diff --git a/packages/vite/src/node/watch.ts b/packages/vite/src/node/watch.ts
new file mode 100644
index 00000000000000..e33070dac1212e
--- /dev/null
+++ b/packages/vite/src/node/watch.ts
@@ -0,0 +1,38 @@
+import type { WatchOptions } from 'types/chokidar'
+import colors from 'picocolors'
+import type { Logger } from './logger'
+import { isWSL2 } from './utils'
+
+export function resolveChokidarOptions(
+  logger: Logger,
+  options: WatchOptions | undefined,
+  optionName: string
+): WatchOptions {
+  const { ignored = [], ...otherOptions } = options ?? {}
+
+  const resolvedWatchOptions: WatchOptions = {
+    ignored: [
+      '**/.git/**',
+      '**/node_modules/**',
+      '**/test-results/**', // Playwright
+      ...(Array.isArray(ignored) ? ignored : [ignored])
+    ],
+    ignoreInitial: true,
+    ignorePermissionErrors: true,
+    ...otherOptions
+  }
+
+  if (isWSL2 && resolvedWatchOptions.usePolling === undefined) {
+    logger.warn(
+      colors.yellow(
+        colors.bold(`(!) `) +
+          'Default file system watching might not work with your setup due to the limitation of WSL2. ' +
+          'HMR and other features will not work when file system watching is not working. ' +
+          `To suppress this warning, set true or false to "${optionName}.usePolling". ` +
+          'More information: https://vitejs.dev/config/server-options.html#server-watch'
+      )
+    )
+  }
+
+  return resolvedWatchOptions
+}

From 608181ce6ac7dbffceb3b8e18c47af1816c52e4b Mon Sep 17 00:00:00 2001
From: sapphi-red <green@sapphi.red>
Date: Mon, 11 Jul 2022 01:41:58 +0900
Subject: [PATCH 08/10] chore: tweak warning message

Co-authored-by: Bjorn Lu <bjornlu.dev@gmail.com>
---
 packages/vite/src/node/watch.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/vite/src/node/watch.ts b/packages/vite/src/node/watch.ts
index e33070dac1212e..1d0bcf762772ef 100644
--- a/packages/vite/src/node/watch.ts
+++ b/packages/vite/src/node/watch.ts
@@ -26,7 +26,7 @@ export function resolveChokidarOptions(
     logger.warn(
       colors.yellow(
         colors.bold(`(!) `) +
-          'Default file system watching might not work with your setup due to the limitation of WSL2. ' +
+          'Default file system watching might not work with your setup due to a limitation of WSL2. ' +
           'HMR and other features will not work when file system watching is not working. ' +
           `To suppress this warning, set true or false to "${optionName}.usePolling". ` +
           'More information: https://vitejs.dev/config/server-options.html#server-watch'

From da90b2f4f73036acf2a87c3f74d9cc90bcbaab0e Mon Sep 17 00:00:00 2001
From: sapphi-red <green@sapphi.red>
Date: Fri, 12 Aug 2022 08:46:44 +0900
Subject: [PATCH 09/10] fix: remove warning

---
 packages/vite/src/node/build.ts        |  4 +---
 packages/vite/src/node/server/index.ts |  9 ++++-----
 packages/vite/src/node/utils.ts        | 19 -------------------
 packages/vite/src/node/watch.ts        | 19 +------------------
 4 files changed, 6 insertions(+), 45 deletions(-)

diff --git a/packages/vite/src/node/build.ts b/packages/vite/src/node/build.ts
index be4ce76dfe0c6a..174e5a33d9169a 100644
--- a/packages/vite/src/node/build.ts
+++ b/packages/vite/src/node/build.ts
@@ -506,9 +506,7 @@ async function doBuild(
       }
 
       const resolvedChokidarOptions = resolveChokidarOptions(
-        config.logger,
-        config.build.watch.chokidar,
-        'build.watch.chokidar'
+        config.build.watch.chokidar
       )
 
       const { watch } = await import('rollup')
diff --git a/packages/vite/src/node/server/index.ts b/packages/vite/src/node/server/index.ts
index c3451069d96790..ee58ca6564753c 100644
--- a/packages/vite/src/node/server/index.ts
+++ b/packages/vite/src/node/server/index.ts
@@ -301,11 +301,10 @@ export async function createServer(
   )
   const { middlewareMode } = serverConfig
 
-  const resolvedWatchOptions = resolveChokidarOptions(
-    config.logger,
-    { disableGlobbing: true, ...serverConfig.watch },
-    'server.watch'
-  )
+  const resolvedWatchOptions = resolveChokidarOptions({
+    disableGlobbing: true,
+    ...serverConfig.watch
+  })
 
   const middlewares = connect() as Connect.Server
   const httpServer = middlewareMode
diff --git a/packages/vite/src/node/utils.ts b/packages/vite/src/node/utils.ts
index 930efec8e2dbf8..85f85adf3cf550 100644
--- a/packages/vite/src/node/utils.ts
+++ b/packages/vite/src/node/utils.ts
@@ -1144,22 +1144,3 @@ export const isNonDriveRelativeAbsolutePath = (p: string): boolean => {
   if (!isWindows) return p.startsWith('/')
   return windowsDrivePathPrefixRE.test(p)
 }
-
-/**
- * returns `true` for WSL2 including docker running on WSL2
- *
- * https://github.com/microsoft/WSL/issues/423#issuecomment-844418910
- */
-export const isWSL2 = (() => {
-  const release = os.release()
-  // Example: `5.10.102.1-microsoft-standard-WSL2`
-  if (release.includes('WSL2')) {
-    // "Docker Desktop for Windows with WSL2 backend" and "Docker installed in WSL" comes here too
-    return true
-  }
-
-  // Windows Example: `10.0.19044`
-  // WSL1 Example: `4.4.0-19041-Microsoft`
-  // Docker Desktop for Windows with WSL2 backend Example: `5.10.76-linuxkit`
-  return false
-})()
diff --git a/packages/vite/src/node/watch.ts b/packages/vite/src/node/watch.ts
index 1d0bcf762772ef..378610e28f3799 100644
--- a/packages/vite/src/node/watch.ts
+++ b/packages/vite/src/node/watch.ts
@@ -1,12 +1,7 @@
 import type { WatchOptions } from 'types/chokidar'
-import colors from 'picocolors'
-import type { Logger } from './logger'
-import { isWSL2 } from './utils'
 
 export function resolveChokidarOptions(
-  logger: Logger,
-  options: WatchOptions | undefined,
-  optionName: string
+  options: WatchOptions | undefined
 ): WatchOptions {
   const { ignored = [], ...otherOptions } = options ?? {}
 
@@ -22,17 +17,5 @@ export function resolveChokidarOptions(
     ...otherOptions
   }
 
-  if (isWSL2 && resolvedWatchOptions.usePolling === undefined) {
-    logger.warn(
-      colors.yellow(
-        colors.bold(`(!) `) +
-          'Default file system watching might not work with your setup due to a limitation of WSL2. ' +
-          'HMR and other features will not work when file system watching is not working. ' +
-          `To suppress this warning, set true or false to "${optionName}.usePolling". ` +
-          'More information: https://vitejs.dev/config/server-options.html#server-watch'
-      )
-    )
-  }
-
   return resolvedWatchOptions
 }

From 967f1b23de50a447e833fd0a5c1daa782599e6dc Mon Sep 17 00:00:00 2001
From: sapphi-red <green@sapphi.red>
Date: Fri, 12 Aug 2022 08:53:57 +0900
Subject: [PATCH 10/10] docs: mention about docker

---
 docs/config/server-options.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/config/server-options.md b/docs/config/server-options.md
index c3a7b88acc50d4..5092622e5d9f5e 100644
--- a/docs/config/server-options.md
+++ b/docs/config/server-options.md
@@ -188,7 +188,7 @@ export default defineConfig({
 
 ::: warning Using Vite on Windows Subsystem for Linux (WSL) 2
 
-When running Vite on WSL2, file system watching does not work when a file is edited by Windows applications (non-WSL2 process). This is due to [a WSL2 limitation](https://github.com/microsoft/WSL/issues/4739).
+When running Vite on WSL2, file system watching does not work when a file is edited by Windows applications (non-WSL2 process). This is due to [a WSL2 limitation](https://github.com/microsoft/WSL/issues/4739). This also applies to running on Docker with a WSL2 backend.
 
 To fix it, you could either: